The ConfigurationInstallerListener can be used to add, change or remove entries from e.g. propertiy-files. Removing entries does not work as supposed when a entry should be removed regardless of it's value.
"key2" will be removed, but "key1" isn't removed, but should be so also.
I've tested in 5.0.0-rc5-SNAPSHOT, but the problem should exist since 2010.